444 M. De la Rive on Chemico -capillary Actions. 



We think that this is sometimes the case, as, for example, in the 

 electrolysis of two liquids placed end to end in the path of the 

 current, so as only to communicate by the intervention of capil- 

 lary spaces, and therefore without being able to mix. But, fur- 

 ther, the phenomena of exosmose, of endosmose, and dialysis 

 show that there may be a positive influence arising either from 

 the fact that the liquids are only in contact by very small sur- 

 faces, or from the nature of the solid which serves as envelope 

 for the capillary spaces. 



The phenomena which M. Becquerel has observed seem also 

 to indicate that the relative nature of the solution and of the 

 porous solid is not without influence, and in general he attri- 

 butes the effects he has perceived to the production of electricity. 

 According to him, when the two solutions are not united by a 

 solid conductor, a case in which obviously a couple is formed, 

 the small layer or the liquid column contained in the capillary 

 space acts as this solid conductor ; or at all events the sides of 

 the insulating material (generally glass) of the capillary space 

 perform the function when they are moistened by a liquid which 

 is itself a conductor. In this manner we should explain the 

 reduction against the sides of those metals whose solutions are 

 in contact with them. M. Becquerel, among other proofs in 

 support of this explanation, mentions that, according to M. E. 

 BecquerePs researches, the liquid columns contained in capillary 

 spaces conduct better than corresponds to the law of diameters. 



We must confess to some hesitation in admitting the prece- 

 ding explanation. We shall first ask whether, in the case in 

 question (that is, when there is a chemical action between two 

 solutions separated from each other, either by diaphragms or by 

 capillary spaces which enable them to be in contact without 

 mixing), electricity does really come into play. That electricity 

 really does intervene when the two solutions thus arranged are 

 connected by an external metallic conductor cannot be doubted ; 

 for then a couple is formed, and the ends of the conductor are 

 true electrodes, which receive the deposits arising from the elec- 

 trolytic decomposition. But when the two solutions are merely 

 in contact without mixing, being separated by a porous dia- 

 phragm or by a capillary space, electromotive force is un- 

 doubtedly developed in the two liquid surfaces in contact, a de- 

 velopment followed by a chemical action, and by the production 

 of an electrical current ; but the current is in this case molecular 

 or local, and can only be perceived when the two liquids are 

 united by a solid conductor; it would seem to us to be rather 

 the result than the cause of the chemical action which takes place. 

 Instead, then, of assuming that the liquid enclosed in the capil- 

 lary space acts as a solid conductor, it would seem more natural 



